As an absorptive covering protecting material applied to a wound, there is generally used a gauze for a medical use because it is thin and soft as well as highly bibulous, wherein the gauze is soft textile fabrics rough woven using yarn of cotton, silk or the like and, after weaving, is refined and bleached, and disinfected. For example, it is said that at a pin insertion portion into which a pin for an injury outside fixer is inserted, epidermal cells appear on a wound surface during five to seven days after an operation and fibroblasts produce collagen and various stroma so that blood vessels are actively regenerated. As a result, it is better to maintain the condition in which a pinhole is contracted with no infection and no scabs are observed, and it is also required to arrange a milieu in which an appropriate temperature, a humidity and an oxygen concentration can be maintained with no microorganisms, no foreign bodies and no necrotic tissues occurring in this stage. To meet these requirements, a so-called end-divided gauze which has an incision at a pin insertion portion is caught.
However, since an absorptiveness and a liquid-holding property of the gauze are insufficient, when an amount of an exudate from the wound is large, the exudate cannot be absorbed appropriately so that a leakage of the exudate occurs to make clothes, sheets or the like foul and unsanitary, or to cause too much trouble because the gauze has to be frequently exchanged in order to prevent the exudate from leaking. At the same time, scabs occur when the exudate is not absorbed into the gauze so that the regenerated cells may be unglued together with the scabs, or that autosensitization dermatitis may be caused by the exudate to delay the wound healing accompanied with eruptions or itching.
In addition, since drop-out fibers (lint) tend to occur from the above-mentioned gauze, the drop-out fibers easily adhere to the wound when the wound is directly covered with the gauze. Therefore, it is not preferable from the sanitary viewpoint to directly cover the wound with the gauze. Further, since the wound tends to be dried easily when using this gauze, the wound is often dried with the drop-out fibers attached to the wound, for example, when the end-divided gauze by the wound at the insertion portion of the pin for the injury outside fixer, at the insertion portion of the drain tube or the like, thereby making it extremely difficult to remove the end-divided gauze. Particularly, in the case that the wound is dried, not only the drop-out fibers separated from the gauze body but also the gauze body itself adheres to the wound and is dried. As a result, the regenerated cells with the scabs may be unglued when the gauze body is taken off from the wound, thereby bring a patient pain as well as causing a delay of the wound healing.
Furthermore, since the above-mentioned gauze is flexible, it cannot be fixed as it is. Therefore, a rubber sheet for press fixation has to be placed over the gauze in order to fix the gauze on the pin of an injury outside fixer. In this case, however, for example, if the wound has swollen, an impression caused by the rubber sheet for press fixation may remain as well as contact dermatitis might occur around the wound, so that the use of rubber sheet is not desirable.
Additionally, as for other absorptive wound covering protecting materials, use of a sponge of polyurethane or polyester has been considered, however, the sponge is not preferable in this case since its bibulousness is inferior and bullae occurs on the skin.
Therefore, as for an absorptive wound covering protecting material being excellent in an absorptiveness and a liquid-holding property without occurring drop-out fibers, which prevents a wound from being dried and besides has a certain shape-maintaining ability so as to make an attachment to the wound easy, and further can be directly applied to the wound, an absorptive wound covering protecting material has been proposed in Japanese Patent Number 3072596, that comprises a cellulose sponge characterized in that the cellulose sponge is prepared by performing a heat treatment in a prescribed temperature range on a sponge raw solution containing no reinforcement that is obtained by mixing viscose and crystalline mirabilite as main raw materials, so as to allow the sponge raw solution to be solidified in a thin thickness, so that the cellulose sponge is formed to be in a sheet form.
Although this material is the most preferable absorptive wound covering protecting material comprising the above-mentioned cellulose sponge so far as shown above, which is excellent in an absorptiveness and a liquid-maintaining ability with regard to the exudate from the wound, the material absorbs a large amount of exudate to degrade the shape-maintaining ability so that the material becomes flexible. As a result, when the absorptive wound covering protecting material is removed from the wound, it may be transformed so as to be difficult to operate. And besides, it is difficult for the absorptive wound covering protecting material to absorb a liquid with a high viscosity, although the material has a high absorptiveness to a liquid.
In addition, since the absorptive wound covering protecting material contains no reinforcement such as fibers and the like in order to prevent drop-out fibers from occurring, it is required to take care not to break the material when it is removed in a dried condition. Moreover, it cannot be denied that the material absorbs a larger amount of the exudate from the wound than necessary so that the strength of the material is reduced, and an attention should be paid not to break the absorptive wound covering protecting material when it is removed.
Furthermore, the absorptive wound covering protecting material only absorbs and maintains the exudate from the wound and it does not particularly enhance a hemostasis wound healing effect. For example, in the case that the amount of the exudate from the pin insertion portion of an injury outside fixer is especially large, it takes more days to be required for wound contraction at the pin insertion portion after an operation, compared to the case in which the amount of the exudate is small. However, since it is important that a pinhole at the pin insertion portion contracts as soon as possible after the operation so that the condition with no signs of infection is maintained, it has been desired to develop an absorptive wound covering protecting material which makes the wound contraction at the pin insertion portion be of excellent quality even in the case of a large amount of the exudate and besides has a certain shape-maintaining ability to make an attachment to the pin insertion portion of the injury outside fixer easy, and further can be directly applied to the wound.